In the related art, when continuous printing is being performed in an image forming apparatus, the temperature around an image forming unit may be excessively increased. In such a case, the image forming apparatus may temporarily interrupt the image forming processes until the temperature drops back below some upper threshold temperature. On the other hand, in order to prevent condensation of humidity inside the image forming unit, the image forming apparatus attempts to keep the image forming unit above some predetermined temperature using a anti-humidity heater when the temperature drops too far. However, when the image forming apparatus includes a anti-humidity heater, image forming operations may sometimes be unintentionally interrupted due to the heat generated by operations of the anti-humidity heater. As a result, printer performance may be degraded.